486 Avenue over Monighan Ck
Deuel County, South Dakota · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 486 Avenue over Monighan Ck in Deuel County, South Dakota, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1954, making it 71 years old at the 2025 inventory.
- It carries about 143 vehicles a day (traffic count year 2022).
- Its listed owner is the county highway agency.
- It is one of 43 of the 72 inventoried bridges in Deuel County rated fair (59.7%); 13 (18.1%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated August 2024, on a 12-month routine inspection cycle.
- It is coded scour critical (NBI item 113 = 3): scour critical: foundations unstable for the assessed or calculated scour.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (44.81327, -96.4794)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 148 ft |
| Location | 1W & 1.5N Gary |
| NBI structure number | 000000020200114 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | August 2024 |
| Inspection interval (item 91) | 12 months |
| Scour (item 113) | 3: scour critical: foundations unstable for the assessed or calculated scour |
Source: FHWA National Bridge Inventory, 2025 data as reported by the South Dakota department of transportation.
Busiest bridges in Deuel County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I029 over Deer Ck | 1971 | 7,560 | Fair |
| I029 S over 471 Ave | 1973 | 4,870 | Fair |
| I029 N over 471 Ave | 1973 | 4,870 | Fair |
| I029 S over Peg Munky Run Ck | 1973 | 4,870 | Fair |
| I029 N over Peg Munky Run Ck | 1973 | 4,870 | Fair |
| I029 S over 184 St | 1973 | 4,830 | Fair |
All bridges nearby: Deuel County, SD bridge conditions · every bridge in Deuel County · South Dakota bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.